Toner, developer, and image forming method

Abstract

To provide a toner including: a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.

1 . A toner comprising:
 a toner material that contains at least a binder resin, a pigment, and a pigment dispersant,   wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and   wherein the pigment contains at least aluminum phthalocyanine.   
     
     
         2 . The toner according to  claim 1 , wherein the pigment dispersant contains at least one of a polyester-based pigment dispersant, an acrylic pigment dispersant, and a polyurethane-based pigment dispersant. 
     
     
         3 . The toner according to  claim 1 , wherein the pigment dispersant has a melting point of 20° C. to 80° C. 
     
     
         4 . The toner according to  claim 1 , wherein the amount of the pigment dispersant is 1 part by mass to 100 parts by mass per 100 parts by mass of the pigment. 
     
     
         5 . The toner according to  claim 1 , wherein the pigment further contains copper phthalocyanine, and the mass ratio of the copper phthalocyanine to the aluminum phthalocyanine is 40:60 to 90:10. 
     
     
         6 . The toner according to  claim 1 , wherein the toner material further contains a wax. 
     
     
         7 . The toner according to  claim 1 , wherein the toner material further contains a binder resin precursor and a wax. 
     
     
         8 . The toner according to  claim 1 , wherein the toner is produced by a method which comprises:
 dispersing or emulsifying in an aqueous medium an oil phase containing the toner material, to produce particles; and   aggregating the particles.   
     
     
         9 . The toner according to  claim 1 , wherein the toner is produced by a method which comprises:
 adding in an aqueous medium a dispersion liquid and an oil phase, the dispersion liquid containing a binder resin precursor composed of a modified polyester resin, the oil phase containing a fine particle dispersant;   dissolving a compound that is crosslinkable with the binder resin precursor;   dispersing the oil phase in the aqueous medium to prepare an emulsified dispersion liquid; and   allowing the binder resin precursor to undergo crosslinking reaction or extension reaction in the emulsified dispersion liquid.   
     
     
         10 . The toner according to  claim 5 , wherein the copper phthalocyanine and aluminum phthalocyanine are mixed together by solvent salt milling. 
     
     
         11 . The toner according to  claim 5 , wherein the toner is produced by dry-mixing the toner material followed by melt-kneading. 
     
     
         12 . The toner according to  claim 11 , wherein in the toner material the copper phthalocyanine and aluminum phthalocyanine are mixed together in the form of powder. 
     
     
         13 . A developer comprising:
 a toner which comprises a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.   
     
     
         14 . An image forming method comprising:
 forming a latent electrostatic image on a latent electrostatic image bearing member;   developing the latent electrostatic image with a toner to form a visible image;   transferring the visible image to a recording medium; and   fixing the image to the recording medium,   wherein the toner comprises a toner material that contains at least a binder resin, a pigment, and a pigment dispersant, wherein the pigment dispersant has an acid value of 20 mgKOH/g to 50 mgKOH/g and an amine value of 1 mgKOH/g to 50 mgKOH/g, and wherein the pigment contains at least aluminum phthalocyanine.